Heretofore it has been common to provide a glass sheet with a border for subsequent utilization as a shelf, a cooktop panel or the like. If the border is an injection molded polymer/copolymeric encapsulation, it is common to utilize a bonding agent to affix the injection molded polymeric/copolymeric frame or border to a peripheral edge of the glass sheet. In U.S. Pat. No. 5,785,047 granted to the assignee of the present invention on Jul. 28, 1998, there is disclosed a cooktop, hob top or the like which includes an injection molded encapsulation surrounding a peripheral edge of a cooktop panel with peripheral surfaces of the latter having a primer applied thereto, such as Chemlok AP-134 one-coat primer and/or Chemlok EP 6962-50A/P primer, each manufactured by Lord Corporation of 2000 West Grand View Blvd., P.O. Box 10038, Erie, Pa. 16514-10038. The primer augments the adhesion between the peripheral edge of the Ceran.RTM., glass or equivalent panel and the encapsulation, frame or border which preferably is Santoprene.RTM. manufactured by Advanced Elastomer Systems L.P.
In order to achieve ease of cleaning and maintenance, uppermost surfaces of the cooktop, the injection molded encapsulation or border and an associated trim piece are substantially flush. However, utilization of primer, adhesive or an equivalent bonding agent to affix an extruded frame to the glass or Ceran.RTM. panel presents numerous problems, both during manufacture and when in use. Obviously, the application of a primer or a bonding agent necessitates additional cost for the material utilized and the additional costs involved in applying the primer carefully and selectively to the periphery of the Ceran.RTM. or glass panel. Delamination can also occur in use, particularly upon primer breakdown and attendant debonding of the frame and glass panel.
In lieu of injection molding a frame to a periphery of a glass sheet, it is also common to utilize a multi-part plastic frame of the type disclosed in U.S. Pat. No. 4,934,541. The multi-part plastic frame requires the separate manufacture of two frame members which are then separately assembled and united with a glass panel by ultrasonic welding. This process avoids delamination when primer breaks down and/or loses its bonding efficacy, particularly during long term use under adverse conditions. However, the costs of manufacturing multi frame members and uniting the same through ultrasonic welding is also cost prohibitive.
Each of these two approaches present more problems than solutions. The injection molding operation presents an aesthetically pleasing product, yet the costs of primer and its application is undesirably prohibitive, particularly when delamination can occur either because of ineffective priming during manufacture and/or the existence of gaps and voids which can be attacked when in use resulting in delamination. Ultrasonic welding precludes delamination, but multi-step manufacturing is cost-prohibitive. Ideally, the best of both worlds would be a "flush-to-front" interlocked, injection molded border and glass sheet lacking primer or bonding material which is relatively strong, can be abused to a considerable extent absent deterioration, is aesthetically pleasing, can be readily cleaned, and can be manufactured at minimum costs.